CVD Substrate Fault Detection Using Real-Time Optical Patterns
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Solution Overview
Problem
Existing methods for identifying faulty or incorrectly inserted substrates in a CVD reactor are complex and inefficient, lacking a straightforward approach to detect deviations during the deposition process.
Innovation Solution
The method involves obtaining reference patterns during the deposition process using optical sensors, calculating these patterns in real-time, and comparing them with patterns obtained from the same process to identify faulty substrates by analyzing temperature and layer thickness measurements, utilizing Fourier transformation and noise analysis to detect deviations from a mean value or threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If reference patterns are obtained from previous deposition processes and stored for comparison, then substrate faults can be identified by comparing with stored patterns, but the method becomes complex and inefficient due to data management and comparison overhead
Solution Approach 1:
The patent applies preliminary action by calculating reference patterns from measurement values obtained during the same deposition process before comparison. The computing device calculates reference patterns from measurement values of substrates processed in the same batch, enabling real-time fault detection without relying on complex historical data management from previous processes.
Solution Approach 2:
The system uses self-service by generating reference patterns from the current process data itself. The measurement values from the ongoing deposition process are used to create reference patterns that are immediately available for comparison, eliminating the need for external reference databases and simplifying the identification method.
2Productivity
If optical sensors continuously measure substrate properties during deposition, then real-time fault detection is enabled, but the measurement and comparison process becomes more complex
Solution Approach 1:
The patent replaces complex mechanical measurement systems with optical sensors that non-contactively measure substrate properties. The optical sensors detect measurement values such as reflectance or temperature during deposition, and a computing device processes these signals to generate patterns for fault detection, simplifying the physical measurement process while enabling continuous monitoring.
Solution Approach 2:
The system monitors changes in optical parameters (such as reflectance, absorption, or temperature) during the deposition process. By tracking parameter variations in real-time and comparing them against reference patterns, the system enables continuous fault detection without complex mechanical intervention.
3Reliability
If multiple optical sensors are used to measure different substrate properties, then comprehensive fault detection is achieved, but the system complexity and cost increase
Solution Approach 1:
The patent employs multi-functional optical sensors that can detect multiple substrate properties using the same sensing mechanism. A single optical sensor system can measure various parameters such as layer thickness, uniformity, and temperature by analyzing different aspects of the optical signal, reducing the need for multiple specialized sensors while maintaining comprehensive detection capability.
Solution Approach 2:
The system merges multiple measurement functions into a unified optical sensing and processing platform. The computing device integrates data from various optical measurements and combines them into comprehensive patterns for fault detection, consolidating what would otherwise require separate measurement systems into a single coordinated approach.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for continuous identification of faulty substrates by dynamically updating reference patterns, providing real-time detection and potential warnings or process aborts based on deviations, enhancing the reliability and efficiency of substrate handling in CVD reactors.
Implementation Method 1
In particular this takes place by means of reflectance measurements
Implementation Method 2
A susceptor, on which the substrates lie in a regular arrangement, for example in a circular arrangement about a center, is heated with a heating device
Implementation Method 3
The reactive gases decompose pyrolytically in the gas phase within the process chamber, or on the surface of the substrate, so that layers are deposited on the substrates
Implementation Method 4
a treatment process of the substrates within a CVD reactor housing
Data Source
AI summary
With the aid of one or more optical sensors, substrates which are faulty or have been incorrectly inserted in a CVD reactor are identified. The one or more optical sensors sense properties of the surfaces of the substrates, for example layer thickness or temperature, before or during a treatment process of the substrates within the CVD reactor housing. The measurement values provided by the sensors can be plotted in the form of a measurement curve, and patterns are obtained from the measurement curve, each pattern corresponding to one of the substrates. The patterns are compared with each other or with a mean calculated from the patterns.